A wireless charging technology relates to a method using an electromagnetic induction to make a current flow for charging a battery so that a magnetic field generated from a first coil in a charging pad induces an electromotive force across a second coil coupled to the battery. The wireless charging technology can be applicable to a communication device or an electric vehicle which requires a massive battery. The wireless charging technology has advantages of reducing a risk such as a leakage current because there are no exposed points of contact and overcoming a poor or faulty performance caused by a defective wire.
As a wireless charging technique becomes widespread, various charging pads have been suggested to supply wireless power signals. Generally, a charging pad includes a board or a plate including a coil, or an antenna, transmitting a wireless power signal and a circuit supplying, or controlling, the wireless power signal with the coil or the antenna according to a wireless charging technology.
FIG. 1 shows a conventional structure of a wireless charging device 100.
As shown, the wireless charging device 100 includes a shielding plate fastening at least one coil 102, 104 and a circuit board 120 supplying a power into the coil 102, 104. In order to reduce an overall size of the wireless charging device 100 and to avoid that a noise occurred at the circuit board 120 interrupts or interferes a performance of the coil 102, 104, the coil 102, 104 and the circuit board 120 can be placed on opposite sides of the shielding plate 110. The coil 102, 104 can be coupled with the circuit board 120 via a coil lead wire 106.
The coil lead wire 106 is bent to electrically connect the coil 102, 104 to a connection port 122 of the circuit board 120 which is placed on the opposite side of the shielding plate 110. The coil lead wire 106 is soldered onto the connection port 122. To solder the coil lead wire 106 onto the connection port 122, the coil lead wire 106 should be long enough to indurate a part of the coil lead wire 106 with an epoxy so as to protect a soldering portion of the coil lead wire 106 and to prevent a wire snaps by an excessive force. Thus, soldering between the connection port 122 and the coil lead wire 106 can make a wasted space P2 from an edge where the coil lead wire 106 is bent to the connection port 122 of the circuit board 120. The wasted space P2 can be an obstacle to arranging plural components on the circuit board effectively and miniaturizing the wireless charging device 100.
Further, as long as the coil lead wire 106 surrounds edges of the shielding plate 110 and the circuit board 120, the coil lead wire 106 should be bent. The bent coil lead wire 106 might become two week for an external force such as a vibration. If the coil lead wire 106 is exposed to an external force such as a vibration for many hours, a bent portion of the coil lead wire 106 could be damaged or cut off. This can be a disadvantage in durability of a wireless charger.